Area Forecast Discussion
Issued by NWS Duluth, MN

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FXUS63 KDLH 251131
AFDDLH

Area Forecast Discussion
National Weather Service Duluth MN
631 AM CDT Mon Mar 25 2024

.KEY MESSAGES...

- Long duration "winter" storm continues today through Tuesday.
  No changes to winter weather warnings with this forecast.

- Additional snow accumulation of 1 to 5 inches in northwest
  Wisconsin, 3 to 10 inches in northeast Minnesota. Total
  snowfall ranges of 6 to 15 inches remain likely.

- A period of freezing rain still possible (20-40%) in northwest
  Wisconsin this morning. Freezing rain is also possible
  (30-50%) in portions of northeast Minnesota tonight and early
  Tuesday morning. Ice accumulation of up to around 2 tenths of
  an inch is forecast from the freezing rain.

- The winter storm will depart Tuesday afternoon through early
  Wednesday morning. Light snow showers may linger through
  Wednesday.

&&

.DISCUSSION...
Issued at 512 AM CDT Mon Mar 25 2024

Challenging storm system will continue to bring wintry weather
to the Northland through tomorrow evening. Biggest concerns this
morning are related to the northward progression of a warm air
aloft and how that will affect precipitation types, the
potential for light freezing rain as that warm nose advances
northward, and pockets of freezing drizzle hidden within the
larger areas of snow this morning.

The 08Z RAP suggests the 850 mb warm nose has pushed northward
into Price County. KPBH still reported light snow as of 0930Z.
It may take a few more hours for the warm layer to become deep
enough to melt the snow completely. Meanwhile successive waves
of 925-700 mb frontogenesis continue to advect northward. A
shortwave trough and associated localized vort max propagated
north-northeastward from northern Iowa around 04Z to Iron and
Ashland counties per the GOES-East water vapor imagery as of
0930Z. There is a localized enhancement in snow rates on the
western periphery of this feature which stretched from Lake
Mille Lacs to near Cotton and Brimson as of 0930Z. The
frontogenesis enhanced snow bands have been struggling to push
north of a St. Cloud to Mora to Hayward line. There have been
reports of freezing drizzle which correspond with local minima
of radar reflectivity over the past few hours. Think that trend
will continue through this morning. Forcing for ascent at this
point seems to have a significant mesoscale component with the
surface low still situated over southwest Kansas.

As the warm nose progresses northward today over northwest
Wisconsin, we expect a change to sleet or freezing rain and then
over to all rain. Left headline timings alone for now. Winter
Storm Warning for most of northwest Wisconsin ends at 1 PM.
Strong and gusty winds will develop along the North Shore this
afternoon into tonight, so left the Blizzard Warning unchanged
also. Confidence in blizzard conditions developing has trended
lower over the past 36 hours. By early evening there is a risk
the snow will change to sleet or freezing rain, which will end
the blizzard conditions if they develop.

Warmer air aloft doesn`t progress as far west as earlier
forecasts by tonight, reducing the risk of mixed precipitation
from the Brainerd Lakes and Aitkin areas. Freezing rain and
sleet mix chances remain from the I-35 corridor north to the
Twin Ports and up the North Shore tonight. Ice accumulations of
a tenth or two are possible with a 30-50% chance mix precip
develops at all.

The system will lift north-northeastward from the southern
Plains into Wisconsin and northeast Ontario by 06Z Wednesday.
Precipitation should change back to snow before tapering off
Tuesday afternoon through Wednesday morning. Cold air advection
and cyclonic flow aloft will keep a chance of light snow showers
and additional light accumulation in the picture through
Wednesday night and possibly Thursday. Additional accumulation
of an inch or two is possible.

There remains another clipper system next weekend which will
bring another shot of wintry weather to the Northland.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 629 AM CDT Mon Mar 25 2024

Poor flight conditions today with LIFR frequently occurring in
snow and eventually fzra this afternoon for the eastern TAF
sites. I do expect a wide range of conditions oscillating from
VFR to LIFR and back with the banded nature of the precipitation
with this large winter storm. I left the TAFs towards the lower
end of flight cats and ignored the VFR as I believe that any VFR
will be short-lived. There may be periodic fzdz between breaks
in snow bands. Winds will be out of the east and gust to 25 to
30 knots giving blowing snow too. Accumulating snow expected at
all TAF sites.

&&

.MARINE...
Issued at 404 AM CDT Mon Mar 25 2024

Onset of gales appears to be later than earlier forecast.
Therefore we have adjusted the start time of the Gale Warnings
for this afternoon except for the Two Harbors to Duluth to Port
Wing areas where gales near the Twin Ports will likely begin by
7 AM. We also extended the Gale Warning for the North Shore
until 1 AM Wednesday as there will likely be a period of gales
after winds back northwesterly during that time allowing for
enhanced downslope flow off the high terrain of the North Shore.
Otherwise forecast remains on track with strong east and
northeast winds today eventually backing northwesterly Tuesday
afternoon and Tuesday night. Winds and waves will gradually
subside as the strong low pressure system departs the region.
Conditions will likely be hazardous to smaller vessels into mid-
week at least.

&&

.DLH WATCHES/WARNINGS/ADVISORIES...
MN...Winter Storm Warning until 7 PM CDT Tuesday for MNZ010>012-018-
     019-025-026-033>038.
     Blizzard Warning until 7 PM CDT Tuesday for MNZ020-021.
WI...Winter Storm Warning until 7 PM CDT Tuesday for WIZ001.
     Winter Storm Warning until 1 PM CDT this afternoon for
     WIZ002>004-006>009.
MARINE...Small Craft Advisory until 4 PM CDT Tuesday for LSZ121-148.
     Small Craft Advisory until 1 PM CDT this afternoon for
     LSZ140>143.
     Gale Warning from 1 PM this afternoon to 1 AM CDT Wednesday
     for LSZ140>143.
     Small Craft Advisory until 7 AM CDT this morning for LSZ144-
     145.
     Gale Warning until 1 PM CDT Tuesday for LSZ144-145.
     Small Craft Advisory until 4 PM CDT this afternoon for LSZ146-
     147-150.
     Gale Warning from 4 PM this afternoon to 1 PM CDT Tuesday for
     LSZ146-147-150.

&&

$$

DISCUSSION...Huyck
AVIATION...Wolfe
MARINE...Huyck


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